The purpose of this study was to investigate the characteristics of physical fitness in baseball pitchers and infielders focusing on variations in power output ability and stretch-shortening cycle (SSC) ability in field tests. Twenty-five male university pitchers and 22 university infielders participated. They performed five kinds of jumping (Standing triple jump (STJ), Standing double leg triple jump (SDTJ), Standing long jump (SLJ), Counter movement jump (CMJ), 5 rebound jumps (RJ)), and five kinds of medicine ball throw (Overhead throw (OT), Back throw (BT), Push of upper limb (Push), Shoulder horizontal adduction (SHA) and Twist of trunk throw (Twist)). Push, SHA and Twist were performed purely concentrically (concentric throw: CT) and with SSC movement (rebound throw: RT). These powers were assessed using the Throw index (Tauchi et al., 2006), and pre-stretch augmentations (Walshe et al., 1996) were calculated. It was found that: 1) OT, BT and SDTJ in pitchers were significantly higher than in infielders, and that there were significant correlations between pitched ball speed and OT, BT, and SDTJ. 2) Push RT-index and Push CT-index in infielders were significant higher than in pitchers, and significant correlations were found between thrown ball speed, batted ball speed and Push RT-index and Push CT-index in infielders. 3) SHA augmentation in infielders was significantly higher than in pitchers, and there was a significant correlation between thrown ball speed and SHA augmentation in infielders. 4) Twist of trunk power did not differ between pitchers and fielders. These results indicate that baseball pitchers and infielders obtain different physical fitness characteristics through the differences in their movement forms and required abilities.